Utovlan contains a progestogen (a synthetic progesterone) called norethisterone. Each tablet has 5mg of norethisterone in it. There is a contraceptive pill called micronor which contains 350mcg norethisterone. This is 15 times less the amount of progestogen. Therefore if you were taking norethisterone continuously throughout the cycle it would act as a contraceptive. However, the drug is usually only taken for anything between 3 to 20 days. In answer to your exact question with regard to ovulation, about 25% of women taking a progesterone only contraceptive stop ovulating. But these women take the tablets continuously every day with no break. The contraceptive effect is usually due to thickening of the cervical mucous and alteration in fallopian tube motility, making it harder for sperm to reach the egg. If fertilisation does occur, progesterone only pills make the womb less responsive so implantation shouldn't occur. In summary, utovlan should not be relied upon as a contraceptive, due to infrequency of taking and the fact that it is unlicenced for this purpose. I hope this answers your question.